How do I make a full screen video play on button click?

At the top of your page, add a container with your video with the ID “full-page-video” and an X with the class “close-full-page-video” and make sure your button has the class “watch-video”

The JS (that includes the logic of stopping the video so an invisible video doesn’t keep playing):
$('.watch-video').click(function() { $('#full-page-video').fadeIn(); });
$('.close-full-page-video').click(function() {
var $frame = $('#full-page-video iframe');
// saves the current iframe source
var vidsrc = $frame.attr('src');
// sets the source to nothing, stopping the video
$frame.attr('src','');
// sets it back to the correct link so that it reloads immediately on the next window open
$frame.attr('src', vidsrc);
$('#full-page-video').fadeOut();
});